Most Common Claim Denial Reasons (Data-Backed)
The most common claim denial reasons are missing or inaccurate claim data, authorization problems, incomplete patient information, coding errors and non-covered services,…
Denial Codes
A denial code is the standardized reason a payer gives for not paying all or part of a claim line. It appears on the 835 electronic remittance or paper EOB as a Claim Adjustment Reason Code (CARC), paired with a group code such as CO, PR, or OA and often a Remittance Advice Remark Code (RARC).
This category is for billers, coders, and AR follow-up staff who need more than a one-line definition. Each article covers one denial in depth: what triggers it, how payers apply it, and the steps to correct, appeal, or prevent it. Start with the CO-97 bundling denial guide, then use the NCCI PTP table lookup walkthrough to check whether a code pair is actually bundled. For prevention, see clearinghouse NCCI scrubbing setup and building a CO-97 denial tracking dashboard. Coverage and authorization denials are covered in CO-96 non-covered charges and CO-197 criteria at three commercial payers.
For a quick code-by-code reference, use the denial codes lookup page; this archive holds the full articles behind it.
Denial Code FAQs
What is the difference between CO and PR denials?
CO (Contractual Obligation) means the adjustment is the provider’s responsibility under the payer contract, so the patient cannot be billed for it. PR (Patient Responsibility) means the amount can be billed to the patient, such as a deductible, coinsurance, or copay. The same CARC can carry either group code.
Should every denial be appealed?
No. Many denials are fixed faster with a corrected claim, such as a missing modifier, a wrong diagnosis pointer, or a demographic error. Appeals fit when the claim was correct and the payer misapplied a policy or edit. Check the CARC, RARC, and payer policy first, then choose the route.
How to Appeal a Denied Medicare Claim: The 5 Levels Explained
A Medicare Part A or Part B claim appeal is the formal process a provider, supplier or beneficiary uses to challenge an…
CPT 87798 Denied for 13 Units: Why It Happens and How to Fix It
CPT 87798 is being denied for 13 units because payers have moved this code into active enforcement in 2026, and 13 units billed on a single date of service trips every automated edit that enforcement triggers.
CPT 90839 and 90840 Denied by Medicaid: What It Means and How to Fix It
When Connecticut Medicaid denies CPT 90839 and 90840 with the reason “coverage/program guidelines were not met”, it is not saying the crisis session did not happen.
CPT 15771 and 15772 Denial: How to Fix “Primary Service Code Was Not Submitted”
If you are billing CPT 15771 and 15772 and receiving the denial message “The primary service code was not submitted therefore the secondary code is not allowed”, you are not alone. It is one of the most common fat grafting add-on code denials.
CO-96 Denial Code: What Non-Covered Charges Mean in Cosmetic Billing
CO-96 is one of the denial codes that shows up across every specialty, every payer, and every billing department regardless of how experienced the team is.
CO 97 Denial Code: What It Means and How to Work It (2026 Guide)
Claim denials don’t just slow down your revenue. They erase it. In 2025, Experian Health’s 3rd Annual State of Claims Survey found that 41% of healthcare providers had at least 1 in 10 claims denied, marking the third consecutive year…
Step-by-step guide to searching NCCI PTP tables on CMS.gov
Before you spend time on a modifier, a corrected claim, or an appeal for a CO 97 denial, there’s one lookup that tells you whether any of that effort is worth it: the NCCI Procedure-to-Procedure (PTP) edit table.
Clearinghouse NCCI scrubbing setup: Guide to enabling pre-submission edit checking by PM platform
Every CO 97 denial that gets caught before submission costs nothing. The same denial caught after submission costs an average rework fee, plus the time to research the NCCI pair, fix the modifier, and resubmit.
Guide to building a CO97 denial tracking dashboard in your PM system
Working CO 97 denials one claim at a time will always be reactive. The same NCCI bundling mistake can repeat across dozens of claims before anyone notices a pattern, because most billing teams review denials individually rather than in aggregate.